I'd usually buy them either new or "almost new" with very few miles on them. The one I bought at 5,200 miles died at 267k miles. The one I bought at 50k miles (IIRC), died at 270k miles. The one I bought new (and used a lot for family trips), is approaching 300k miles and still going strong.

Of course, the style of driving has a huge impact. We typically driving more hi-way miles and less stoplight-to-stoplight.